On a surface of a substrate, a protective film (hard coating film) to enhance scratch resistance, film strength, film hardness, scratch strength, pencil strength, water resistance, chemical resistance, etc. of the substrate has been heretofore formed, and various protective films have been proposed according to the type of the substrate.
Further, for the purposes of preventing static electrification of surfaces of transparent substrates, such as display panels of cathode-ray tubes, fluorescent display tubes and liquid crystal display boards, and preventing light reflection therefrom, formation of transparent films (transparent conductive films) having antistatic function and anti-reflection function on these surfaces has been carried out.
The recent substrates are desired to take scratches very rarely from the viewpoint of appearance, and therefore, the transparent films are desired to have high adhesion to the substrates and much higher film strength. However, if fine particles are used in order to improve adhesion, there is brought about a new problem that the light reflection from the surface is strengthened to cause glare of display devices, resulting in that the display image cannot be seen.
It is, therefore, an object of the present invention to provide a transparent film-forming coating liquid capable of forming a transparent film that is excellent not only in scratch resistance, film hardness, scratch strength and adhesion to a substrate but also in haze and anti-glare properties. It is another object of the present invention to provide a display device having a front panel constituted of a substrate with such a transparent film.
In order to solve such problems as mentioned above, the present inventors have earnestly studied, and as a result, they have found that by incorporating inorganic oxide particle groups, in each of which inorganic oxide particles are linked in the form of a chain, into a transparent film, the transparent film is enhanced in the scratch resistance, film hardness, scratch strength and adhesion to a substrate, and in addition, anti-glare properties of the film can be enhanced without deterioration of haze. Based on the finding, the present invention has been accomplished.